1. Field of the Invention
The field of the invention is that of electronic devices for generating synchronization signals. More specifically, the technical field is that of very high resolution synchronization signals, the temporal accuracy of the signals being less than a nanosecond. These devices are in particular used in the laser subsystems that deliver high-energy, ultra-brief laser pulse trains, the duration of the pulses being of the order of a few hundreds of femtoseconds and their energy being of the order of a terawatt.
These subsystems more often than not comprise a large number of optoelectronic elements needed for generating, amplifying and formatting the laser pulses and elements for controlling, monitoring and measuring these pulses. Now, the pulses emitted have a very brief duration, so it is vitally important to synchronize the various elements of the subsystem with a high temporal accuracy so as to ensure both optimal operation of the subsystem and the best possible reproducibility of the emitted pulses.
2. Description of the Prior Art
The current synchronization devices present a certain number of drawbacks. On the one hand, the internal clock of these various devices is not necessarily perfectly synchronized with an external signal taken from an element of the system to be synchronized. On the other hand, when the system comprises a large number of elements to be synchronized it becomes impossible to synchronize them all with a single synchronization device. In this case, several synchronization devices are used, these devices being synchronized between themselves by so-called trigger devices. These triggers are produced from internal clock signals of the synchronization devices. These clock signals are periodic. It can be demonstrated that the triggering accuracy is equal to one period of the clock signal. For example, for a clock signal emitted at a frequency of 100 megahertz, the synchronization accuracy is then equal to one period, or 10 nanoseconds. This accuracy is not sufficient, for certain applications, to permit a perfect synchronization of the various elements of the system.